Meanwhile, Boko Haram has killed '2,000 people' in one town

Boko Haram militants have killed at least 100 people in Baga, Nigeria, according to the district's head Abba Hassan, although some reports suggest as many as 2,000 people may have died.

The Reuters news agency reports Hassan gave the figure during a telephone news conference to journalists.

Two locals said the Islamist insurgents began shooting indiscriminately and burning buildings on Tuesday evening in several raids targeting the civilian population. These raids carried through to Wednesday after they seized the town on Saturday.

Soldiers protecting Baga had fled over the weekend.

But there is still some confusion over the details of the attacks, with different officials giving different accounts to different media groups. NBC, citing Ahmed Khalifa, a senator in the area's Borno state, has reported 2,000 people are unaccounted for and "towns are just gone, burned down".

Separately the BBC reports that up to 2,000 people could have been killed in the raids, citing a "senior government official in the area" named Musa Alhaji Buka.

Boko Haram, whose name translates as “Western education is sin”, said in September they were planning on establishing their own calipathe in Nigeria.

More: Meanwhile, in Nigeria, Boko Haram is carving out its own 'caliphate'